TDS (Total Dissolved Solids)

webbstock · 01/12/2007, 12:07 PM

I've noticed that many reefers seem to get very concerned about TDS in a particular water supply. Now before I get Flamed let me say that I do understand TDS and their implications (check out http://www.reefkeeping.com/issues/20...ture/index.php), but my point is for the average hobbyist should TDS be of that great a concern?

So first let me start by saying that if you have you own RO unit, then you want to test TDS to make sure that it is working well, plus if you are extremely serious about your reef tank and measure and dose everything you can, then yes the TDS of your beginning water is imperative.

But for lots of us, if we are using water source X and our tank has been stable and everything is thriving, and we test the TDS one day and find out that the source is constantly high, I don't feel that we should freak out. (I mean if the source continuously has a high TDS, not as if there was a malfunction in the RO unit etc.). Obviously, if the fish/corals are doing well then they are acclimated to the conditions. Now if we were experiencing algae blooms, or high nitrates etc, then we would need to question if our high TDS at the water source is to blame.

Obviously some compounds that contribute to TDS are more detrimental than others and it would be good to know what compound is adding to a high TDS. But again, for the average reefer, I would think that keeping your water parameters stable is more important than getting very worried about a consistent high TDS in source water when the end result is fine.

drummereef · 01/12/2007, 12:12 PM

You won't get totally pure water, 0 tds ,without a DI stage. I think it is of utmost importance to me and can see a drastic change in water quality when my tds gets above 1. Diatoms are the first thing to come.

kipher · 01/12/2007, 01:04 PM

Looks like you understand TDS pretty well. I'd like to share alittle bit of my experience here if you don't mind. I set up my tank with the intension of being FO and had it running for about a month using tap water and had a bad Diatom problem. I then decided that i would rather go reef, so broke down my tank changed the substrate (from crushed coral to stand) and the filtration system (from a wet/dry to LR biological) and bought an RO/DI. The tank has now been running on RO/DI water now for about a month and a half and not a single algea break out yet. (keeping my fingers crossed and knocking on wood at the same time here) Hope my experience helps.

Granted this has alot to say about my local water company. Others may experience things differently.

Edit: I'd like to add that the TDS of my tap is around 390...after RO/DI TDS is at 0. And the difference in water quality is amazing. I'd also like to second Drummer's comments.

rustybucket145 · 01/12/2007, 01:20 PM

The only problem with your opinion is that over time, through evaporation and top off the solids (whatever they may be) will increase. Now what started as an acceptable level of a certain solid could become toxic over the course of say.... a year through evap and top off. Then you have a huge problem on your hands. Your rock and sand could have possibly absorbed high levels of that toxin so even a 100% water change would only temporarily help until the toxin is leeched from the rocks/sand and back into the water column. A nightmare that many people have lived through.

Can a tank be kept without a RO/DI filter? Of course! Is it smart? I think not! I guess it's a decision every hobbiest has to make at one time or another. My decision came one day when I was looking in my tank and just thinking about how much money I had in corals, rocks, sand and livestock. Why not spend the extra $150 to put my mind at ease? At that point it was a no brainer for me. I bought a unit the very next day and never looked back. I know that I am putting clean clear and solid free water into my tank, keeping it healthy and algea/problem free.

If you want to play roulette with your tank be my guest, but trust me it will catch up to you some day.

AZDesertRat · 01/12/2007, 01:33 PM

The biggest problem in my mind is the inconsistency in tap water. I have been a certified treatment plant operator and Supervisor for over 30 years so I have some knowledge of the subject at hand. As an example in the Phoenix area we have several major sources of surface water plus groundwater wells that can all be used individually or blended together. Depending on the time of year, water demands, canal availability, storm events, treatment techniques, chemical additions etc. the tap water quality and TDS changes dramatically. These changes can and do happen in a matter of hours in most cases. Today it is cloudy and we are expecting rain so I will guarantee you tap water quality will be different for the next week or so.
Without a TDS meter or knowing a buddy in the treatment plant who can warn you of changes coming down the pike the average person would never suspect a thing. I have seen my TDS go from 450 to 1000 in a matter of hours, along with that the pH and alkalinity change dramatically due to the treatment change. I did use tap water for the first 8 years of reef keeping but could never understand the changes in tank conditions when I had not done anything different myself. Granted this was in the 1980s and very early 1990s before good test kits, meters and such were commonplace as they are today.
I recommend having your own RO/DI unit if for nothing else so you have a consistent water source. You then control the water quality as you decide when to change filters or DI resin and what to store the treated water in. You are not at the mercy of your water utility, LFS, water vending machine or whatever. That way you know when something happens in your tank you can eliminate water as the source of the problem since you made it and tested it yourself. Its the best investment you can make for yoursystem as water is the single largest ingredient in your reef.

webbstock · 01/12/2007, 02:03 PM

Great replies so far, but just a bit of claification

I wasn't advocating using tap water (not a good idea), but rather if you use water from a LFS/water machine (ex. culligan's) that maybe has a certain TDS level.

Quote:

The only problem with your opinion is that over time, through evaporation and top off the solids (whatever they may be) will increase

Don't forget that lots of compounds that add to TDS will be metabolized by your inhabitants and that if you do regular water changes that will slow the accumulation of your tank's TDS.

Quote:

looking in my tank and just thinking about how much money I had in corals, rocks, sand and livestock. Why not spend the extra $150 to put my mind at ease?

I think this statement is exactly right, when you reach that point in your reef, then taking the next step is very logical. However, I still think that for someone who is relatively new and more on the "average" side of reef-keeping, using LFS or water machine water is fine as there are more important factors to worry about first.

rustybucket145 · 01/12/2007, 02:10 PM

Quote:

Don't forget that lots of compounds that add to TDS will be metabolized by your inhabitants and that if you do regular water changes that will slow the accumulation of your tank's TDS.

What if it poisons them over time as they metabolize it? Just as an example... lead? I know there's no lead in our water I'm just using it as an example for X.

Quote:

I still think that for someone who is relatively new and more on the "average" side of reef-keeping, using LFS or water machine water is fine as there are more imortant factors to worry about first.

You are exactly right! If someone would have told me in the beginning that I HAD to buy a RO/DI I would have laughed in their face. I had lots of other stuff that I needed to get for the tank besides a water machine. I like it when people 'ease' into the hobby. It seems that people who go out and spend thousands of dollars in one weekend for their first tank usually give it up in the first year. There's a very steep learning curve when it comes to saltwater aquariums. I still learn new things all the time! Keep it simple in the beginning and take the leaps when you are ready.

AZDesertRat · 01/12/2007, 02:10 PM

There are lots of things though that are cumulative and are not removed by water changes so do accumulate and get higher and higher, copper being one. If we all were lucky enough to know the makeup of the TDS the decision would be easier, but since TDS is not an exact measurement of specific ions only a general guide of everything conductive its best to avoid it all together.

kfowler · 01/12/2007, 02:14 PM

IMO, this is similar to the whole QT'ing issue. You can certainly find people who have never QT and have never had a problem with disease or such. However that doens't mean that it's a better husbandry practive to QT.

For me, I want to reduce as many variables as I can. I use RO water because that's a fairly inexpensive and easy way to control what enters my tank.

webbstock · 01/12/2007, 02:23 PM

AZdesertRat-

Your statement is true in that copper would still build up over time, but with water changes the accumulation would be much slower. Plus for about 10 dollars you can use a media like cuprisorb which can remove 1.3 grams of copper (quite a bit) from water and is rechargable

For Everone-

Also when considering TDS don't forget that TDS doesn't account for lots of other detrimental compounds like organic compounds, bacteria etc. So you could have water with a TDS of 0, but a huge organic load (like bacterial toxins) that is much worse for your tank than water with a TDS of 10 due to calcium carbonate, but no organic load.

webbstock · 01/12/2007, 02:27 PM

Ohh or better yet, as a microbiologist I like this, we could add specific bacteria, like Bifidobacterium longum to our tanks to remove heavy metals. :P

http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum

Mimbler1 · 01/12/2007, 02:33 PM

AZ desertRats description of his water system quality is valid for ours in Wichita, KS as well. Using water from any source (LFS/grocery store filtered water) that has significant TDS could and would wind up with you putting water with significant PO4 and nitrates among other things in your tank depending on the time of year. Other locales are more consistent. Unless you know which camp you are in, I would get RO/DI before I would get a skimmer,
Mike

01/12/2007, 12:07 PM	#1
webbstock Registered Member Join Date: Oct 2006 Location: Washington DC area Posts: 436	TDS (Total Dissolved Solids) I've noticed that many reefers seem to get very concerned about TDS in a particular water supply. Now before I get Flamed let me say that I do understand TDS and their implications (check out http://www.reefkeeping.com/issues/20...ture/index.php), but my point is for the average hobbyist should TDS be of that great a concern? So first let me start by saying that if you have you own RO unit, then you want to test TDS to make sure that it is working well, plus if you are extremely serious about your reef tank and measure and dose everything you can, then yes the TDS of your beginning water is imperative. But for lots of us, if we are using water source X and our tank has been stable and everything is thriving, and we test the TDS one day and find out that the source is constantly high, I don't feel that we should freak out. (I mean if the source continuously has a high TDS, not as if there was a malfunction in the RO unit etc.). Obviously, if the fish/corals are doing well then they are acclimated to the conditions. Now if we were experiencing algae blooms, or high nitrates etc, then we would need to question if our high TDS at the water source is to blame. Obviously some compounds that contribute to TDS are more detrimental than others and it would be good to know what compound is adding to a high TDS. But again, for the average reefer, I would think that keeping your water parameters stable is more important than getting very worried about a consistent high TDS in source water when the end result is fine.

01/12/2007, 12:12 PM	#2
drummereef Team RC Member Join Date: Jul 2006 Location: STL Posts: 14,754	You won't get totally pure water, 0 tds ,without a DI stage. I think it is of utmost importance to me and can see a drastic change in water quality when my tds gets above 1. Diatoms are the first thing to come. __________________ -Brett 180g Marineland Starfire In-Wall 278 gallon system

01/12/2007, 01:04 PM	#3
kipher Registered Member Join Date: Nov 2006 Location: Edwardsville, IL Posts: 429	Looks like you understand TDS pretty well. I'd like to share alittle bit of my experience here if you don't mind. I set up my tank with the intension of being FO and had it running for about a month using tap water and had a bad Diatom problem. I then decided that i would rather go reef, so broke down my tank changed the substrate (from crushed coral to stand) and the filtration system (from a wet/dry to LR biological) and bought an RO/DI. The tank has now been running on RO/DI water now for about a month and a half and not a single algea break out yet. (keeping my fingers crossed and knocking on wood at the same time here) Hope my experience helps. Granted this has alot to say about my local water company. Others may experience things differently. Edit: I'd like to add that the TDS of my tap is around 390...after RO/DI TDS is at 0. And the difference in water quality is amazing. I'd also like to second Drummer's comments. __________________ Brian SEASL & SLASH member For the Best of both Worlds!!!! Current Tank Info: 75G reef, 95 lbs LR, 29g tank as my DIY fuge/sump w/ Quiteone Model 3000 (780gph) return pump, ASM G-2 Skimmer, 1 - 170gph Penguin 660 PH , Seio 2600, 2500gph MJ Mod, Typhoon III RO/DI, 2x250W MH (10K XM's) & 2-36" 96W VHO Actinic

01/12/2007, 01:20 PM	#4
rustybucket145 Registered Member Join Date: Jan 2006 Location: valdosta, ga Posts: 3,707	The only problem with your opinion is that over time, through evaporation and top off the solids (whatever they may be) will increase. Now what started as an acceptable level of a certain solid could become toxic over the course of say.... a year through evap and top off. Then you have a huge problem on your hands. Your rock and sand could have possibly absorbed high levels of that toxin so even a 100% water change would only temporarily help until the toxin is leeched from the rocks/sand and back into the water column. A nightmare that many people have lived through. Can a tank be kept without a RO/DI filter? Of course! Is it smart? I think not! I guess it's a decision every hobbiest has to make at one time or another. My decision came one day when I was looking in my tank and just thinking about how much money I had in corals, rocks, sand and livestock. Why not spend the extra $150 to put my mind at ease? At that point it was a no brainer for me. I bought a unit the very next day and never looked back. I know that I am putting clean clear and solid free water into my tank, keeping it healthy and algea/problem free. If you want to play roulette with your tank be my guest, but trust me it will catch up to you some day. __________________ 400gals of various tanks in the same system. Current Tank Info: 2 175w MH, 2 VH0 Actinics, Lots of Live Rock, tons of copepods, a Fat Mandarin Goby, Niger Trigger, Yellow Tang, Falco Hawkfish, Bi-Color Pseudo, numerous soft, SPS and LPS Corals

01/12/2007, 02:14 PM	#9
kfowler Premium Member Join Date: Dec 2003 Location: Michigan Posts: 1,095	IMO, this is similar to the whole QT'ing issue. You can certainly find people who have never QT and have never had a problem with disease or such. However that doens't mean that it's a better husbandry practive to QT. For me, I want to reduce as many variables as I can. I use RO water because that's a fairly inexpensive and easy way to control what enters my tank. __________________ Kevin "You cannot achieve what you are not willing to pursue." Current Tank Info: 20g Mixed Reef

01/12/2007, 01:33 PM	#5
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	The biggest problem in my mind is the inconsistency in tap water. I have been a certified treatment plant operator and Supervisor for over 30 years so I have some knowledge of the subject at hand. As an example in the Phoenix area we have several major sources of surface water plus groundwater wells that can all be used individually or blended together. Depending on the time of year, water demands, canal availability, storm events, treatment techniques, chemical additions etc. the tap water quality and TDS changes dramatically. These changes can and do happen in a matter of hours in most cases. Today it is cloudy and we are expecting rain so I will guarantee you tap water quality will be different for the next week or so. Without a TDS meter or knowing a buddy in the treatment plant who can warn you of changes coming down the pike the average person would never suspect a thing. I have seen my TDS go from 450 to 1000 in a matter of hours, along with that the pH and alkalinity change dramatically due to the treatment change. I did use tap water for the first 8 years of reef keeping but could never understand the changes in tank conditions when I had not done anything different myself. Granted this was in the 1980s and very early 1990s before good test kits, meters and such were commonplace as they are today. I recommend having your own RO/DI unit if for nothing else so you have a consistent water source. You then control the water quality as you decide when to change filters or DI resin and what to store the treated water in. You are not at the mercy of your water utility, LFS, water vending machine or whatever. That way you know when something happens in your tank you can eliminate water as the source of the problem since you made it and tested it yourself. Its the best investment you can make for yoursystem as water is the single largest ingredient in your reef.

01/12/2007, 02:10 PM	#8
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	There are lots of things though that are cumulative and are not removed by water changes so do accumulate and get higher and higher, copper being one. If we all were lucky enough to know the makeup of the TDS the decision would be easier, but since TDS is not an exact measurement of specific ions only a general guide of everything conductive its best to avoid it all together.

01/12/2007, 02:23 PM	#10
webbstock Registered Member Join Date: Oct 2006 Location: Washington DC area Posts: 436	AZdesertRat- Your statement is true in that copper would still build up over time, but with water changes the accumulation would be much slower. Plus for about 10 dollars you can use a media like cuprisorb which can remove 1.3 grams of copper (quite a bit) from water and is rechargable For Everone- Also when considering TDS don't forget that TDS doesn't account for lots of other detrimental compounds like organic compounds, bacteria etc. So you could have water with a TDS of 0, but a huge organic load (like bacterial toxins) that is much worse for your tank than water with a TDS of 10 due to calcium carbonate, but no organic load.

01/12/2007, 02:27 PM	#11
webbstock Registered Member Join Date: Oct 2006 Location: Washington DC area Posts: 436	Ohh or better yet, as a microbiologist I like this, we could add specific bacteria, like Bifidobacterium longum to our tanks to remove heavy metals. :P http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum

01/12/2007, 02:33 PM	#12
Mimbler1 Registered Member Join Date: Oct 2000 Location: Wichita, KS Posts: 575	AZ desertRats description of his water system quality is valid for ours in Wichita, KS as well. Using water from any source (LFS/grocery store filtered water) that has significant TDS could and would wind up with you putting water with significant PO4 and nitrates among other things in your tank depending on the time of year. Other locales are more consistent. Unless you know which camp you are in, I would get RO/DI before I would get a skimmer, Mike __________________ Mike